Climate change: Rain melting Greenland ice sheet 'even in winter'By David ShukmanScience editor8 hours agoShare this with Facebook Share this with Messenger Share this with Twitter Share this with Email ShareImage copyrightJOSEPH COOKImage captionAfter it rains the surface darkens, which speeds up meltingRain is becoming more frequent in Greenland and accelerating the melting of its ice, a new study has found.

Scientists say they're "surprised" to discover rain falling even during the long Arctic winter.

The massive Greenland ice-sheet is being watched closely because it holds a huge store of frozen water.

And if all of that ice melted, the sea level would rise by seven metres, threatening coastal population centres around the world.

Precipitation usually falls as snow in winter - rather than as rain - which can balance out any melting of the ice in the summer.

What did the scientists find?The scientists studied satellite pictures of the ice-sheet which reveal the areas where melting is taking place.

And they combined those images with data gathered from 20 automated weather stations that recorded when rainfall occurred.

The findings, published in the journal The Cryosphere, show that while there were about two spells of winter rain every year in the early phase of the study period, that had risen to 12 spells by 2012.

On more than 300 occasions between 1979-2012, the analysis found that rainfall events were triggering a melting of the ice.

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Most of these were in summertime, when the air often gets above zero.

But a growing number happened in winter months when the permanent dark of the polar winter would be expected to keep temperatures well below freezing.

What happens when it rains?Image copyrightJOSEPH COOKImage captionThe ice after rain in the Kangerlussuaq region, GreenlandThe lead author of the study, Dr Marilena Oltmanns of the GEOMAR ocean research centre in Germany, told BBC News: "We were surprised that there was rain in the winter.

"It does make sense because we're seeing flows of warm air coming up from the South, but it's still surprising to see that associated with rainfall."

Another scientist on the study, Prof Marco Tedesco of Columbia University in New York, said that the increase in rain had important implications.

Even if it falls during winter, and then quickly refreezes, the rain changes the characteristics of the surface, leaving it smoother and darker, and "pre-conditioned" to melt more rapidly when summer arrives.

The darker the ice is, the more heat it absorbs from the Sun - causing it to melt more quickly.

"This opens a door to a world that is extremely important to explore," Prof Tedesco said.

"The potential impact of changes taking place in the winter and spring on what happens in summer needs to be understood."

A smoother surface, particularly a "lens" of ice, will allow meltwater to flow over it much faster and being darker means that more of the Sun's rays are absorbed, further speeding-up the warming process.

Pictures taken by a British research team, caught in a rainstorm on the ice-sheet last year, show how a bright highly reflective landscape of snow and ice was turned into a much darker scene.

Why does this matter?Although Greenland is extremely remote, a vast island lying at the northern end of the Atlantic Ocean, the sheer volume of ice covering it means its fate could have global repercussions.

Image copyrightARWYN EDWARDSImage captionThe Greenland ice sheet in rainy conditions in 2014In stable times, snowfall in winter will balance any ice melted or breaking off into the ocean in summer. But research has shown how in recent decades the ice-sheet has been losing vast amounts of mass.

Although this contributes only a relatively small amount to the rise in the sea-level - with much of the rest coming from thermal expansion as the oceans warm - the fear is that the flow of meltwater could accelerate as temperatures rise.

Two years ago, the BBC reported from Greenland on the risks of faster melting, because of the growth of algae which makes the ice darker and more likely to warm.

This effect of algae is, in addition to darkening, caused by soot and other forms of pollution carried by winds to the Arctic.

This comes amid growing concern that the region as a whole is warming twice as fast as the rest of the planet, which may be influencing the flow of the high-altitude jet stream.

That could disturb weather patterns in Europe and other regions, and may also explain how the flows of warm, moist air from the Atlantic are reaching Greenland, even in winter.

What do other scientists make of this?Prof Jason Box, a glaciologist not involved in the new study, says the research builds on earlier work by him and colleagues published in 2015 that found that summer rainfall could increase the rate of melting.

Their analysis found that because water has a high heat content, it takes only 14mm of rain to melt 15cm of snow, even if that snow is at a temperature of minus 15C.

"There's a simple threshold, the melting point, and when the temperature goes above that you get rain instead of snow," he said.

"So, in a warming climate it's not rocket science that you're going to have more rain than snow, and it's one more reason why the ice sheet can go into deficit instead of being in surplus."

Prof Box has himself experienced sudden rainstorms while camped on the ice-sheet.

"After weeks of sunshine, it started raining on us and it completely transformed the surface - it got darker.

"And I became convinced - only by being there and seeing it with my own eyes - that rain is just as important as strong sunny days in melting the Greenland ice sheet."

NASA researchers burn leftover wood on the Helheim Glacier, which is one of the fastest-moving ice floes in Greenland.Lucas Jackson / Reuters

The Greenland Ice Sheet is the world’s second-largest reservoir of fresh water sitting on the world’s largest island. It is almost mind-bogglingly huge.

If Greenland were suddenly transported to the central United States, it would be a very bad day for about 65 million people, who would be crushed instantly. But for the sake of science journalism, imagine that Greenland’s southernmost tip displaced Brownsville, Texas—the state’s southernmost city—so that its icy glaciers kissed mainland Mexico and the Gulf thereof. Even then, Greenland would stretch all the way north, clear across the United States, its northern tenth crossing the Canadian border into Ontario and Manitoba. Kansas City, Oklahoma City, and Iowa City would all be goners. So too would San Antonio, Memphis, and Minneapolis. Its easternmost peaks would slam St. Louis and play in Peoria; its northwestern glaciers would rout Rapid City, South Dakota, and meander into Montana. At its center point, near Des Moines, roughly two miles of ice would rise from the surface.

Suffice it to say: The Greenland Ice Sheet, which contains enough water to refill the Great Lakes 115 times over, is very large. And it is also falling apart.

A new study finds that the Greenland Ice Sheet added a quarter inch of water to global sea levels in just the past eight years. The research, published Monday in the journal Proceedings of the National Academy of Sciences, covers nearly 20 years previously not included in our detailed understanding of the troubled Greenland Ice Sheet. It finds that climate change has already bled trillions of tons of ice from the island reservoir, with more loss than expected coming from its unstable northern half.

“The glaciers are still being pushed out of balance,” Eric Rignot, a senior scientist at NASA and an author of the paper, told me. “Even though the ice sheet has [sometimes] been extremely cold and had low surface melt in the last year, the glaciers are still speeding up, and the ice sheet is still losing mass.”

The paper casts the transformation of the Greenland Ice Sheet as one of the profound geological shifts of our time. Scientists measure the mass of ice sheets in “gigatons”—each unit equal to 1 billion metric tons, or roughly the same amount of water that New York or Los Angeles uses in a year. Greenland, according to the study, has lost 4,976 gigatons of water since 1972. That’s enough water to fill 16 trillion bathtubs or 1.3 quadrillion gallon jugs. That much water weighs about 11 quadrillion pounds. (A quadrillion is 1 with 15 zeros after it.)

More worryingly, the paper finds that Greenland lost about half of that ice—roughly 2,200 gigatons—in the years between 2010 and 2018. The ice sheet has also failed to gain mass in any year since 1998.

This melting isn’t happening at a steady pace, in other words. Greenland’s demise seems to be accelerating. Think of Greenland as a huge inland ice sea, surrounded by faster-moving ice rivers (which are glaciers) that empty the sea and carry ice to the ocean. The paper finds that those rivers are speeding up, carrying ice out of the island’s core nearly twice as fast now as they did in the 1990s or 2000s.

Read: Ancient Rome’s collapse is written into Arctic ice

That’s an alarming result, because it means glaciers might now be shrinking Greenland from the bottom faster than hot weather can melt it from the top. And researchers believe that bottom-melting glaciers are less stable and more prone to rapid collapse. “If there’s a risk of rapid sea-level rise in the future, it will be associated with glaciers speeding up, and not anything happening at the surface,” Rignot said.

The paper’s findings are stirring in part because they go much further back in time. “A lot of the publications [about Greenland’s mass] start in 2000 or 2002, some go back to 1992, but this is the first time we go back another 20 years,” Rignot said. Historically, most studies of Greenland combine data from radar flybys, GPS beacons, and laser or gravity-sensing satellites. But there’s not enough data from before 1992 to be useful, so that’s when estimates usually stop.

Rignot and his colleagues helped hit upon a new resource. The U.S. Geological Survey’s Landsat satellites have circled the planet nonstop since 1972, imaging every speck of land on Earth every 16 days. This archive—which is a kind of Earth-science version of taking a photo of yourself every day for years—includes hundreds of images of Greenland. Rignot and his team taught a computer how to read those pictures of its icy surface, zooming in especially on the dozens of glaciers that connect the interior ice sheet to the sea.

“It’s looking at two different pictures of a glacier, before and after. [In each frame,] the rocks don’t move but the glacier moves, so it can compare and cross-correlate image points,” Rignot said. “Then the algorithm searches around the window for where the pixel might have gone.”

Read: Studying Greenland’s ice to understand climate change

The team ultimately used this technique to calculate the speed of Greenland’s glaciers from 1972 to 1992. Then they combined that data with modern observations of the ice sheet to estimate its historical mass. (They used a similar method to estimate Antarctica’s ice loss in a paper published earlier this year.)

Rignot and his colleagues relied on another new resource too: OMG!

As in, literally, the project is named OMG, short for Oceans Melting Greenland. OMG is a five-year NASA mission, started in 2016, to study how warmer oceans are eroding Greenland’s waterfront glaciers. Rignot helps lead it. “Thanks to OMG, we’ve been able to construct a [bedrock] model of Greenland that is pretty good under the ice, and is very, very good underneath the ocean,” he said.

Brad Lipovsky, a glaciologist at Harvard who was not connected to the research, said in an email that the results “seem plausible at first glance,” but that scientists would need to carefully check some of the team’s methodology. The overall story of Greenland, he said, is that the ice sheet’s flow is slowly accelerating. This “makes sense,” he said, “because it takes the slowly flowing ice sheet a lot longer to respond than the rapidly evolving atmosphere.”

Rignot believes that the new study should make glaciologists look anew at the speed with which Greenland could collapse. The ice sheet’s bleeding-out could eventually raise global sea levels by as much as 25 feet. So the key question, Rignot said, is “How fast can you make these entities fall apart?” The answer will matter to all of us. The surface of Greenland doesn’t have to move through magic to other parts of the world—already, today, its deluge is on its way

DJ-Another Greenland article. Melt can also be caused by wind eroding the ice and snow and transporting it into warmer seawater. Increased melt make-sometimes-glaciers "grow" while in fact it is a sign of increased transport of melting ice. Another growing problem is earth/icequakes. Direct; moving the ice, indirect; tsunamiwaves. Also warmer seawater is making the region warmer.

Greenland is falling apart! 11 QUADRILLION POUNDS of water lost since 1972 and 286 BILLION TONS of ice lost since 2010 and it's getting worse.

Since 1972, the giant island’s ice sheet has lost 11 quadrillion pounds of water.The Greenland ice sheet contains enough water to fill the Great Lakes 115 times over - and it's falling apart quicker than ever.To get a feel of how large Greenland's ice sheet is, it's about three times bigger than Texas, or six times bigger than Germany.We knew the ice was melting faster and faster - after all, just last year, a study found that the 2012 melting was 4 times faster than in 2003. Now, another study published in PNAS adds even more context, finding that Greenland ice melting has accelerated by 6 times since the 1980s.Between 1980 and 1990, Greenland lost 51 billion tons of ice - an enormous quantity in its own right. However, in only 8 years, from 2010 to 2018, it lost 286 billion tons.The losses are expected to get even worse, says Eric Rignot, Ph.D., a professor at the University of California, Irvine, and lead author of the new study."Going from a 20-year-long record to a 40-year-long record shows us a transition from a climate dominated by natural variability to a climate dominated by climate warming from human emissions of greenhouse gases," Rignot says."Over that time period, the mass loss increased sixfold."We've seen the effects of rising temperatures in Greenland before.It's impressive to see a big glacier calve and break away, but most of the time, the melting is far less dramatic - a steady melt and drip over the (still) glacial surface.Greenland as a whole has already experienced a warming of 2 degrees Celsius (3.6 degrees Fahrenheit), and some areas have warmed by as much as 4 degrees Celsius, this being the main reason for the melting.The importance of this cannot be overstated.If all of the Greenland Ice Sheet melted, the sea level would rise by about 20 feet - but that's not even the main concern.As ice and snow melt, they will leave room to darker soils, which will absorb even more solar energy, further accelerating heating.Also, even if only a fraction of that sea level rise is achieved, the consequences will be devastating. At this point, no matter what we do, some melting and sea level rise is unavoidable.But the consequences can range from serious to absolutely devastating if we continue in the business-as-usual scenario.It's up to us whether we do something to limit the damage.

"If we do something now, it will take 30 years to affect the climate and another few decades to turn the meltdown of glaciers, so probably half of that signal is already written in stone," says Ringot. "But the impact sea level will have on humanity increases with every 10 [centimetres] of sea level rise, and right now we are about to commit to multi-meter sea level rise in the coming century if we don't do something drastic."

DJ-Even when you do not believe "we can save the world", "we passed the last station" we-as humans-have a moral obligation to do everything we can to give next generations, other species, a chance to live.

Greenland has 3 km of ice on it-when the ice will go away Greenland will lift 1 km. This in itself will cause earthquakes and sealevelrise (above the melt of the ice).

We cannot solve our problems with the same thinking we used when we created them.~Albert Einstein

Democracy Dies in DarknessCapital Weather GangThe Greenland ice sheet poured 197 billion tons of water into the North Atlantic in July aloneOngoing extreme melt event continues, with more than half the ice sheet experiencing melting on July 31.Melting ice forms a lake on free-floating ice jammed into the Ilulissat Icefjord during unseasonably warm weather on July 30, 2019, near Ilulissat, Greenland. (Sean Gallup/Getty Images)Melting ice forms a lake on free-floating ice jammed into the Ilulissat Icefjord during unseasonably warm weather on July 30, 2019, near Ilulissat, Greenland. (Sean Gallup/Getty Images)By Andrew Freedman and Jason Samenow August 1, 2019 at 11:10 AM EDTWhen one thinks of Greenland, images of an icebound, harsh and forbidding landscape probably come to mind, not a landscape of ice pocked with melt ponds and streams transformed into raging rivers. And almost certainly not one that features wildfires.

Yet the latter description is exactly what Greenland looks like today, according to imagery shared on social media, scientists on the ground and data from satellites.

An extraordinary melt event that began earlier this week continues on Thursday on the Greenland ice sheet, and there are signs that about 60 percent of the expansive ice cover has seen detectable surface melting, including at higher elevations that only rarely see temperatures climb above freezing.

July 31 was the biggest melt day since at least 2012, with about 60 percent of the ice sheet seeing at least 1 millimeter of melt at the surface, and more than 10 billion tons of ice lost to the ocean from surface melt, according to data from the Polar Portal, a website run by Danish polar research institutions, and the National Snow and Ice Data Center. Thursday could be another significant melt day, before temperatures drop to more seasonable levels.

According to Ruth Mottram, a climate researcher with the Danish Meteorological Institute, the ice sheet sent 197 billion tons of water pouring into the Atlantic Ocean during July.

This is enough to raise sea levels by 0.5 millimeter, or 0.02 inches, in a one-month time frame, said Martin Stendel, a researcher with the institute.

This might seem inconsequential, but every increment of sea-level rise provides a higher launchpad for storms to more easily flood coastal infrastructure, such as New York’s subway system, parts of which flooded during Hurricane Sandy in 2012. Think of a basketball game being played on a court whose floor is gradually rising, making it easier for even shorter players to dunk the ball.

As a result of both surface melting and a lack of snow on the ice sheet this summer, “this is the year Greenland is contributing most to sea-level rise,” said Marco Tedesco, a climate scientist at Columbia University.

Thanks to an expansive area of high pressure enveloping all of Greenland — the same weather system that brought extreme heat to Europe last week — temperatures in Greenland have been running up to 15 to 30 degrees above average this week.

(National Snow and Ice Data Center)At Summit Station, which at 10,551 feet is located at the highest point in Greenland and rarely sees temperatures above freezing, the thermometer exceeded this mark for about 11 hours Tuesday, according to Christopher Shuman, a glaciologist at the University of Maryland-Baltimore County and NASA Goddard Space Flight Center.

The ongoing melt event is being compared to a record extreme heat and melt episode that occurred in Greenland in 2012. While the extent of surface melt during that event may have exceeded this one so far, Shuman found that Summit Station experienced warmth that was greater “in both magnitude and duration” during the current event. The temperature only remained above freezing about half as long in 2012, and the peak temperature reached 34.02 degrees this year, whereas it only hit 33.73 in 2012. During the 2012 extreme event, however, 97 percent of the ice surface experienced melting.

“Like 2012, this melt event reached the highest elevations of the ice sheet, which is highly unusual,” says Thomas Mote, a professor of geography at the University of Georgia. “Both our satellite observations and the ground-based observations from Summit indicated melt on Tuesday.”

“The event itself was unusual that the warm air mass came from the east, and appears to be a part of the air mass that caused the record-breaking heat wave in Europe. Most of our extreme melt days on the Greenland ice sheet are associated with warm air masses moving from the west and south. I cannot recall an instance where we saw such extensive melt associated with an air mass coming from Northern Europe,” Mote said.

The heat, along with below-average precipitation in parts of Greenland, has even sparked wildfires along the Greenland’s non-ice-covered western fringes. Satellite images and photos taken from the ground show fires burning in treeless areas, consuming mossy wetlands known as fen that can become vulnerable to fires when they dry out. These fires can burn into peatlands, releasing greenhouse gases buried long ago through decomposition of organic matter.

A wildfire burns in western Greenland on July 31, 2019. (Orla Joelsen via Twitter)Studies have shown that ice melt periods like the one seen in 2012 typically occur about every 250 years, so the fact that another one is taking place only a few years later could be a sign of how climate change is upping the odds of such events.

According to DMI’s Mottram, the short-term, extreme melt event is a sign of climate change’s increasing influence on the Arctic.

“So yes it’s weather but it shows that in spite of internal variability the background signal of a warming climate is still “winning,” she said via a Twitter message. She said state-of-the-art climate computer models have been unable to simulate events like this, which hampers scientists’ ability to accurately predict Greenland ice melt and, therefore, future sea-level rise.

I have a feeling the problem (us) will fix itself, and a lot sooner than most people believe - if they believe it at all. We can't even feed everyone now, and we're pushing the land to it's limit already. If the population does indeed reach 9-11 billion by mid century, the UN estimates we'll need 75% more food. Access to fresh water is already becoming an issue, and we won't be able to rely on the oceans for food because it's predicted that they'll be effectively fished dry by 2050. With changing weather patterns expected to impact growing regions with devastating results in the next few decades, a perfect storm is heading our way and few people see it.

I honestly believe that global famine is a certainty in the near future, and for the first time since the Black Death we're going to see a massive human die-off. It pains me to think that way being a parent, but we've painted ourselves in this corner and I don't think we have the sense to get ourselves out. I don't believe we're doomed as a species because we're just too adaptable, but just as all the other great civilizations fell, I think this one also has an expiration date and we're fast approaching it.

This is not sustainable.

"Buy it cheap. Stack it deep""Any community that fails to prepare, with the expectation that the federal government will come to the rescue, will be tragically wrong." Michael Leavitt, HHS Secretary.

There is already a "battle for Greenland" from investors loking for mining possibilities. Trump is expected to visit Denmark in september. https://www.rt.com/usa/466607-greenland-trump-buy-report/The "idea of buying a country" may be seen as insulting. Greenland once was part of the EU, sometimes there are "corrections of borders" in good dialogue.

Industry, mining, tourism, are major risks for the Greenland ice.

We cannot solve our problems with the same thinking we used when we created them.~Albert Einstein

DJ-https://forum.arctic-sea-ice.net/index.php/topic,2591.5800.html discussion on the 2019 Arctic Melt Season. Most likely it will end up close to the 2012 record low level. Result will be-certainly with most of the ice surrounding Greenlanden melted-increased glacier landice flow from Greenland into the ocean. And increased rise of the Greenland landmass due to decreased pressure from landice.

Should Greenland prepare for a US invasion ? (With IS-bears as excuse....)The world/Trump is getting crazy !

https://www.rt.com/news/466935-trump-greenland-denmark-meeting/:Frederiksen refused to even entertain the possibility, calling the purchase “absurd” and explaining more than once that “Greenland is not for sale” - and that it isn’t Denmark’s to sell, anyway. Trump, for his part, has floated the idea of purchasing the landmass multiple times, musing that “it would be nice” for strategic purposes.-DJ; Since Denmark is part of EU, and several other (nordic) organizations Trump's approach may increase "unease" even further between those groups and the (present) US.

Trump's idea "you can buy a country" reflects "money rules". That idea is unacceptable for almost all other countries.

We cannot solve our problems with the same thinking we used when we created them.~Albert Einstein

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